Early Rush (1970 - 1975) openly copied the style of Led Zeppelin (mostly on vocal lines).

I would have them in such a list; Jethro Tull started in 1968 and that's pretty early, isn't it? King Crimson's first era sterted in 1969 and finished in 1974 and they not only shaped the progressive genre but also influenced many metal musicians as well. So did Rush.
As for Cream, I thought they were in the list already, but apparently I'm wrong.